Look at Damien's website with step by step guide :

http://mydomotic.blogspot.co.uk/2015/09 ... ystem.html

This looks great. I have just bought Harmony Hub and see activities in Domoticz on my Synology. However I have never tried a script. If you would like to call Volume up command, how should I creat it: - by creating Dummy switch with VolumeUp and Execute script which will contain: ./HarmonyHubControl ...